Vix: Новая страница: «Проблема древняя и как водится связана с попыткой Microsoft навязывать свои стандарты. Откуда берется почтовое вложение winmail.dat вы можете почитать тут: https://support.mozilla.org/ru/kb/chto-oznachaet-vlozhenie-winmaildat сегодня мы решим эту проблему глобально, прокачаем наш postfix сервер...»

2023-06-23T07:41:34Z

Новая страница: «Проблема древняя и как водится связана с попыткой Microsoft навязывать свои стандарты. Откуда берется почтовое вложение winmail.dat вы можете почитать тут: https://support.mozilla.org/ru/kb/chto-oznachaet-vlozhenie-winmaildat сегодня мы решим эту проблему глобально, прокачаем наш postfix сервер...»

Новая страница

Проблема древняя и как водится связана с попыткой Microsoft навязывать свои стандарты. Откуда берется почтовое вложение winmail.dat вы можете почитать тут: https://support.mozilla.org/ru/kb/chto-oznachaet-vlozhenie-winmaildat

сегодня мы решим эту проблему глобально, прокачаем наш postfix сервер

Установим MIMEDefang.
для CentOS

yum install mimedefang
для Ubuntu

apt-get install mimedefang
Настроим MIMEDefang на определенный порт TCP, наша служба будет слушать этот порт. Для этого исправим конфигурацию
для CentOS: /etc/sysconfig/mimedefang
для Ubuntu: /etc/default/mimedefang

дописываем в конце

SOCKET=inet:10185
Отредактируем файл /etc/mail/mimedefang-filter, можете просто вставить текст ниже
# -*- Perl -*-
#***********************************************************************
#
# mimedefang-filter
#
# Suggested minimum-protection filter for Microsoft Windows clients, plus
# SpamAssassin checks if SpamAssassin is installed.
#
# Copyright (C) 2002 Roaring Penguin Software Inc.
#
# This program may be distributed under the terms of the GNU General
# Public License, Version 2, or (at your option) any later version.
#
# $Id$
#***********************************************************************

#***********************************************************************
# Set administrator's e-mail address here. The administrator receives
# quarantine messages and is listed as the contact for site-wide
# MIMEDefang policy. A good example would be 'defang-admin@mydomain.com'
#***********************************************************************
$AdminAddress = 'postmaster@localhost';
$AdminName = "MIMEDefang Administrator's Full Name";

#***********************************************************************
# Set the e-mail address from which MIMEDefang quarantine warnings and
# user notifications appear to come. A good example would be
# 'mimedefang@mydomain.com'. Make sure to have an alias for this
# address if you want replies to it to work.
#***********************************************************************
$DaemonAddress = 'mimedefang@localhost';

#***********************************************************************
# If you set $AddWarningsInline to 1, then MIMEDefang tries *very* hard
# to add warnings directly in the message body (text or html) rather
# than adding a separate "WARNING.TXT" MIME part. If the message
# has no text or html part, then a separate MIME part is still used.
#***********************************************************************
$AddWarningsInline = 0;

#***********************************************************************
# To enable syslogging of virus and spam activity, add the following
# to the filter:
# md_graphdefang_log_enable();
# You may optionally provide a syslogging facility by passing an
# argument such as: md_graphdefang_log_enable('local4'); If you do this, be
# sure to setup the new syslog facility (probably in /etc/syslog.conf).
# An optional second argument causes a line of output to be produced
# for each recipient (if it is 1), or only a single summary line
# for all recipients (if it is 0.) The default is 1.
# Comment this line out to disable logging.
#***********************************************************************
md_graphdefang_log_enable('mail', 1);

#***********************************************************************
# Uncomment this to block messages with more than 50 parts. This will
# *NOT* work unless you're using Roaring Penguin's patched version
# of MIME tools, version MIME-tools-5.411a-RP-Patched-02 or later.
#
# WARNING: DO NOT SET THIS VARIABLE unless you're using at least
# MIME-tools-5.411a-RP-Patched-02; otherwise, your filter will fail.
#***********************************************************************
# $MaxMIMEParts = 50;

#***********************************************************************
# Set various stupid things your mail client does below.
#***********************************************************************

# Set the next one if your mail client cannot handle multiple "inline"
# parts .
$Stupidity{"NoMultipleInlines"} = 0;

# Detect and load Perl modules
detect_and_load_perl_modules();

sub filter {
my($entity, $fname, $ext, $type) = @_;

### Convert TNEF winmail.dat format
### Note: You must install Convert::TNEF and File::Type from CPAN before using this script
if (lc($type) eq "application/ms-tnef" or lc($fname) eq "winmail.dat" ) {
use Convert::TNEF;
use File::Type;
use File::Temp qw(tempfile tempdir);

# Create a unique temporary directory under "/tmp"
my $tnefdir = tempdir(CLEANUP => 1, DIR => "/tmp");
if (not $tnefdir) {
md_graphdefang_log('tnef_fail',"Unable to create temporary directory");
return action_accept();
}

# If we can't Convert the TNEF file for some reason, just accept the attachment and log the
error
my $tnef = Convert::TNEF->read_ent($entity,{output_dir=>"$tnefdir"});
if (not $tnef) {
md_graphdefang_log('tnef_fail',$Convert::TNEF::errstr);
return action_accept();
}

my $ft = File::Type->new();

# Append attachments contained in the winmail.dat file to the message.
for ($tnef->attachments) {
# Determine the mime-type of the file
my $mimetype = $ft->mime_type($_->data);

# File::Type doesn't detect text files well, this is a workaround
if ($mimetype eq "application/octet-stream") {
#Set the mime-type to text/plain if the first 1024 characters are printable
$text_check = substr($_->data,0,1024);
$mimetype = "text/plain" unless $text_check =~ /[^[:print:]s]/;
}

my $tnef_entity = action_add_part($entity, "$mimetype", "base64", $_->data, $_- >longname, "attachment");
md_graphdefang_log('tnef_ext', "File: " . $_->longname . " Type: $mimetype");

# Run each new TNEF-sourced MIME part back through the filter again, this ensures that
bad filenames etc.
# cannot sneak through by being contained in winmail.dat files

filter ($tnef_entity, $_->longname, "", "$mimetype");
}

# Deletes working files
$tnef->purge;

# Remark this if you want still want to keep the original winmail.dat file
return action_drop();
}

# Keep the attachment
return action_accept();
}

# DO NOT delete the next line, or Perl will complain.
1;
Раскрыть
Установим модели Perl Convert::TNEF и File::Type
для CentOS

yum install perl-Convert-TNEF.noarch
второй пакет надо скачать и установить

wget https://ftp.tu-chemnitz.de/pub/linux/dag/redhat/el6/en/x86_64/rpmforge/RPMS/perl-File-Type-0.22-1.el6.rf.noarch.rpm
yum install perl-File-Type-0.22-1.el6.rf.noarch.rpm
для Ubuntu

apt-get install libconvert-tnef-perl
apt-get install libfile-type-perl
Проверим синтаксис Perl
# perl -c /etc/mail/mimedefang-filter
Настроим автозапуск службы MIMEDefang и запустим ее
systemctl enable mimedefang.service
service mimedefang restart
Проверим, слушает ли сервис указанный выше порт
# netstat -tlpn | grep 10185
tcp 0 0 0.0.0.0:10185 0.0.0.0:* LISTEN 7401/mimedefang
Теперь добавим проверку в Postfix, для этого откроем конфиг /etc/postfic/main.cf
и допишем в конце

smtpd_milters = inet:localhost:10185
milter_default_action = accept
готово! Любое письмо, которое будет иметь во вложении winmail.dat, будет обработано нашей службой и вложение будет расшифровано!

* [https://itscience.pro/all/lechim-pochtovye-vlozheniya-winmail-dat/ IT science]

Лечим почтовые вложения winmail.dat - История изменений